Rework wiki page versions index/diff views

- Changed to using the diff-body CSS class
-- Removed unnecessary elements from the CSS style file
- Does a symmetric difference on the array fields to detect differences
- Add more descriptors to the status/changes column
- Specifically add <br> to statuses to cause line breaks

app/javascript/src/styles/specific/wiki_page_versions.scss

@@ -1,22 +1,18 @@
 div#c-wiki-page-versions {
   #a-diff {
-    del, .wiki-other-names-diff-list .removed {
+    ul.wiki-other-names-diff-list li.removed {
       background: var(--wiki-page-versions-diff-del-background);
       text-decoration: none;
     }
 
-    ins, .wiki-other-names-diff-list .added {
+    ul.wiki-other-names-diff-list li.added {
       background: var(--wiki-page-versions-diff-ins-background);
       text-decoration: none;
     }
 
-    .wiki-other-names-diff-list .obsolete {
+    ul.wiki-other-names-diff-list li.obsolete {
       text-decoration: dotted underline;
     }
-
-    span.paragraph-mark {
-      opacity: 0.25;
-    }
   }
 
   #a-index {